Dynamic allocation of power modules for charging electric vehicles

ABSTRACT

Dynamic allocation of power modules for charging electric vehicles is described herein. A power cabinet includes multiple power modules that each are capable of supplying an amount of power to a dispenser. Multiple dispensers are coupled with the same power cabinet. A first power bus couples a first dispenser and switchably connects the power modules to the first dispenser; and a second power bus couples a second dispenser and switchably connects the power modules to the second dispenser. The power cabinet includes a control unit that is configured to cause the power modules to switchably connect and disconnect from the first power bus and the second power bus to dynamically allocate the power modules between the first dispenser and the second dispenser.

FIELD

Embodiments of the invention relate to the field of electric vehiclecharging; and more specifically, to the dynamic allocation of powermodules for charging electric vehicles.

BACKGROUND

Electric vehicle charging stations, sometimes referred to as EVSE, areused to charge electric vehicles (e.g., electric battery poweredvehicles, gasoline/electric battery powered vehicle hybrid, etc.). AnEVSE consists of a Dispenser that connects to the electric vehicle, andpower conversion electronics that may be housed separate power cabinet.Dispensers may be located in designated charging locations (e.g.,similar to locations of gas stations), adjacent to parking spaces (e.g.,public parking spaces and/or private parking spaces), etc.

A group of dispensers may be electrically connected to the same powercabinet. Since the dispensers may not fully be utilized at all times(e.g., an electric vehicle may not be connected to a dispenser or anelectric vehicle may be connected to a dispenser but is not charging oris charging very little), it may be uneconomical to design theinfrastructure to support the maximum capacity of each dispenserconnected to the power cabinet.

SUMMARY

Dynamic allocation of power modules for charging electric vehicles isdescribed herein. A power cabinet includes multiple power modules thateach are capable of supplying an amount of power to a dispenser.Multiple dispensers are coupled with the same power cabinet. A firstpower bus couples a first dispenser and switchably connects the powermodules to the first dispenser; and a second power bus couples a seconddispenser and switchably connects the power modules to the seconddispenser. The power cabinet includes a control unit that is configuredto cause the power modules to switchably connect and disconnect from thefirst power bus and the second power bus to dynamically allocate thepower modules between the first dispenser and the second dispenser.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may best be understood by referring to the followingdescription and accompanying drawings that are used to illustrateembodiments of the invention. In the drawings:

FIG. 1 illustrates an exemplary system for dynamically allocating powermodules for charging electric vehicles according to an embodiment;

FIG. 2 illustrates an example of allocating power modules according toan embodiment;

FIG. 3 illustrates an example of allocating power modules dynamicallyaccording to an embodiment;

FIG. 4 is a flow diagram that illustrates exemplary operations forallocating power modules according to an embodiment;

FIG. 5 is a flow diagram that illustrates exemplary operations fordynamic allocation of the power modules according to an embodiment;

FIG. 6 is a flow diagram that illustrates exemplary operations forallocating power modules according to another embodiment;

FIG. 7 illustrates an embodiment where the power cabinet is split intomultiple power module groups; and

FIG. 8 illustrates an exemplary dispenser according to an embodiment.

DESCRIPTION OF EMBODIMENTS

In the following description, numerous specific details such as logicimplementations, opcodes, means to specify operands, resourcepartitioning/sharing/duplication implementations, types andinterrelationships of system components, and logicpartitioning/integration choices are set forth in order to provide amore thorough understanding of the present invention. It will beappreciated, however, by one skilled in the art that the invention maybe practiced without such specific details. In other instances, controlstructures, gate level circuits and full software instruction sequenceshave not been shown in detail in order not to obscure the invention.Those of ordinary skill in the art, with the included descriptions, willbe able to implement appropriate functionality without undueexperimentation.

A method and apparatus for dynamically allocating power modules forcharging electric vehicles is described herein. The charging systemincludes multiple electric vehicle charging stations (herein referred toas a dispenser) connected to a power cabinet. The power cabinet includesmultiple power modules that can each supply power to any one of thedispensers. The allocation of the power modules may be performeddynamically.

FIG. 1 illustrates an exemplary system 100 for dynamically allocatingpower modules for charging electric vehicles according to an embodiment.The system 100 includes a power source 105 that is connected to thepower cabinet 110 through the AC input terminal 130. The power source105 may be supplying, for example, 400 VAC/480 VAC, 3 phase. The powercabinet 110 includes a housing that includes the power modules 115A-L.Each of the power modules 115A-L can supply power to either of the EVSE150A-B, depending on the allocation of power modules. Thus, each powermodule has the ability to supply power to multiple outputs, one outputat a time. Each of the power modules 115A-L are coupled with the powerand cabinet control unit (PCU) 120 over the PMs to PCU 142, switchablyconnected with the AC input terminal 130 over the bus 132, andswitchably connected with the DC output terminal 135 through the powerbus 140A and the power bus 140B. Each of the power modules 115A-L can beswitchably connected to only one of the power buses 140A-B at a time.For instance, the power module 115A can be connected to the power bus140A or the power bus 140B, but cannot be connected to both of the powerbuses 140A-B at the same time.

The power buses 140A-B are coupled with the DC output terminal 135,which itself is coupled with the EVSE 150A over the output 152A(corresponding with the power bus 140A) and coupled with the dispenser150B over the output 152B (corresponding with the power bus 140B). Thus,the dispenser 150A is capable of receiving power from those of the powermodules 115A-L (if any) that are connected to the bus 140A and thedispenser 150B is capable of receiving power from those of the powermodules 115A-L (if any) that are connected to the bus 140B.

The PCU 120 manages the cabinet cooling including the cooling control144. The PCU 120 communicates with the dispensers 150A-B over thecommunication line 162. The PCU 120 provides SELV supply 160 to thedispensers 150A-B.

In an embodiment, the dispensers 150A-B are coupled with the network180. Each of the dispensers 150A-B may be coupled with the network 180over a wide area network (WAN) link (e.g., cellular (CDMA, GRPS, etc.),WiFi Internet connection, Plain Old Telephone Service, leased line,etc.), or one of the dispensers may be coupled with the network 180 overa WAN link and coupled with the other dispenser over a LAN link (e.g.,Wireless Personal Area Network (WPAN) such as Bluetooth, Zigbee, etc.,Ethernet, Power Line Communication (PLC), WiFi, etc.) and relay messagesbetween the other dispenser and the network 180. The network 180 mayinclude one or more servers that provide services for electric vehiclecharging such as authorization service, accounting service, andreporting service.

The network 180 may store vehicle operator information (e.g., operatoraccount information, operator contact information (e.g., operator name,street address, email address, telephone number, etc.)), chargingsession information (e.g., the duration that an EV connected to adispenser has been charging; the duration that an EV connected to adispenser has been parked in proximity to the dispenser; the timeremaining on each charging session; the type of account associated witheach charging session; the amount of current drawn by the EV during thesession; the percentage of charge complete of the EV during the session;the percentage of charge remaining of the EV; the battery temperature ofthe EV during the session; the type of EV during the session; and/or areservation status of the EV), dispenser configuration information(e.g., the wiring group the dispenser belongs to (as used herein, awiring group corresponds to the physical wiring connection to thecharging cabinet), the capacity of the wiring group (e.g., the breakersize), and/or a trip margin used to prevent false circuit breakertrips), load supply condition information, and/or power moduleinformation (e.g., operating hours of each power module).

Each dispenser 150A-B is configured to control the application of powerto the electric vehicles, which may dynamically change as detailedherein. Each dispenser 150A-B is capable of being connected to anelectric vehicle such as the electric vehicles 170A-B respectively. Thedispensers may support a wired connection for attached charging cords(e.g., with a connector conforming to SAE Electric Vehicle and Plug inHybrid Electric Vehicle Conductive Charge Coupler (J1772_201602),February 2016 (“SAE J 1772”); a connector conforming to the CHAdeMOprotocol) for charging electric vehicles, connector capable ofconnecting to Tesla MotorsTM vehicles, a GB connector, and/or any otherconnector that attaches to an electric vehicle); and/or wirelesscharging (e.g., the dispensers may support inductive charging, and/orconductive charging (e.g., pantograph)).

Exemplary Charging Sequence

Charging service typically begins after an electric vehicle is connectedto a dispenser and after a charging session has been authenticated.There are a number of different ways in which a charging session can beauthenticated. For instance, an electric vehicle operator may request acharging session for their electric vehicle through use of acommunication device (e.g., a WLAN or WPAN device such as a one ortwo-way radio-frequency identification (RFID) device, mobilecommunication device (e.g., laptops, palmtop, smartphone, multimediamobile phone, cellular phone, wearable device, etc.). As a specificexample, if the dispenser (or device connected to the dispenser such asa payment station) includes an RFID reader, the operator may wave/swipethe mobile communication (if an RFID enabled device) near the RFIDreader to request a charging session. The dispenser may forwardinformation read from the RFID reader (e.g., an identifier associatedwith the electric vehicle operator) to the network 180 forauthentication. The network 180 determines whether to grant the chargingsession and replies to the dispenser with the response (e.g., allowed ordenied). Alternatively, the dispenser may locally store authorizationinformation (e.g., a whitelist or blacklist of identifiers) that allowsthe dispenser to determine whether to authorize the charging session. Asanother specific example, an electric vehicle operator may use a mobileapplication on a mobile device to request a charging session on thedispenser. For instance, the operator may select the dispenser using alocator map and then select to request a charging session (typicallyafter logging into the application or otherwise providing usercredentials to the application). The network 180 then determines whetherto grant the charging session and replies to the dispenser with theresponse (e.g., allowed or denied). As another example, the dispensermay be configured to allow for automatic authentication. An example ofautomatic authentication includes ISO 15118 where the electric vehicleoperator requests a charging session by connecting their electricvehicle to the dispenser and that electric vehicle communicates anidentifier (e.g., the vehicles VIN or other identifying information)that is used by the dispenser and/or the network 180 to determinewhether to grant or deny the charging session. Other examples ofautomatic authentication include use of license plate recognition (thelicense plate may be read by the dispenser or other device coupled withthe dispenser and the number used to determine whether to grant or denythe charging session), facial recognition (the dispenser, or otherdevice coupled with the dispenser, may include a camera to take an imageof the electric vehicle operator to determine whether a charging sessionfor the electric vehicle operator should be granted or denied),proximity detection (e.g., WiFi, Bluetooth, Bluetooth LE) that detectswhether a mobile device of the electric vehicle operator or the vehicleitself is in proximity to the electric vehicle and use an associatedidentifier to determine whether to grant or deny the charging session.

The electric vehicle and the dispenser communicate after beingconnected. The dispenser may advertise the available power to thevehicle, which is sometimes referred to as the maximum availablecontinuous current capacity. This advertisement may take the form ofmodulating a signal (e.g., a control pilot signal). The amount of powerthat may be available may be determined by the dispenser based at leastin total site feed and/or demand response information received from thenetwork 180 and/or the amount of power allocated from the power cabinet110. In an embodiment, the electric vehicle may indicate a desiredamount of power it wants to draw, which may change throughout thecharging cycle (e.g., the electric vehicle may send a current command tothe dispenser that the dispenser can use to determine how much power tosupply to the electric vehicle).

In an embodiment, to determine the amount of power allocated from thepower cabinet 110, the dispenser requests the status of the powermodules 115A-L. The status of each power module 115A-L may indicatewhether the power module is currently allocated (e.g., whether it iscurrently connected to a power bus and may indicate which power bus),whether the power module is idle (e.g., not currently connected to apower bus), or whether the power module is offline (e.g., it cannot becontacted). The dispenser may request the status of each power module115A-L directly or may send a request to the PCU 120 which then queriesthe status of the power modules 115A-L and returns the statuses to therequesting dispenser. The status of each power module 115A-L may includean amount of time each power module has been operating. In anotherembodiment, the power cabinet 110 periodically sends status informationof the power modules 115A-L to the dispensers 150A-B and/or to thenetwork 180 (e.g., when the state of one of the power modules changes);which is used by the dispensers to determine the amount of powerallocated from the power cabinet 110.

The requesting dispenser may determine which, if any, power module, iscurrently available, using the power module status information. In suchan embodiment, the dispenser requests allocation of certain ones of theavailable power modules so that the dispenser can charge the connectedelectric vehicle. The requesting dispenser may send a command to eachone of the selected available power modules 115A-L directly (which maybe relayed by the PCU 120) that instructs the selected power module toswitchably connect to the power bus that is connected to the dispenser.For instance, with respect to FIG. 1, the dispenser 150A may transmit acommand to the selected ones of the power modules 115A-L (over thecommunication link 162) that instructs those power modules to switchablyconnect to the power bus 140A.

In another embodiment, the requesting dispenser requests the PCU 120 todetermine which, if any, power module is currently available. In such anembodiment, the dispenser sends a request to the PCU 120 for power (therequest may indicate how much power) and the PCU 120 may select from theavailable power modules (if any) to allocate to the requestingdispenser. The PCU 120 then instructs those selected power modules toswitchably connect to the power bus that is connected to the dispenser.For instance, with respect to FIG. 1, the dispenser 150A may transmit arequest to the PCU 120 for allocation of power (over the communicationlink 162) and the PCU 120 will determine which of the power modules115A-L (if any) are available, select from those available powermodules, and instruct those selected power modules to switchably connectto the power bus 140A.

In another embodiment, the requesting dispenser sends a request forpower to the power cabinet 110. In response to this request, each powermodule that is available to be allocated to the dispenser is thenallocated. The request may be sent to the PCU 120 which then causes theavailable power modules (if any) to be allocated to the requestingdispenser. In this embodiment, each available power module (at least ofthe power module group that can be allocated to the requestingdispenser) is allocated to the requesting power module, regardless ofwhether the electric vehicle and/or the dispenser can support supplyingpower to that amount. For instance, with respect to FIG. 1, thedispenser 150A may transmit a request for power to the PCU 120 whichwill then determine which of the power modules 115A-L (if any) areavailable and cause those power modules to be allocated to the dispenser150A and switchably connect to the power bus 140A. The amount of powermay be more than the dispenser and/or the electric vehicle can support.After the allocation of the available power modules, the dispenser 150Adetermines whether to release any of the power modules, such as theexcess number of power modules that it needs.

The amount of power that the power modules 115A-L can supply to thedispensers 150A-B may not be enough to handle the maximum rating of theconnected dispensers or the maximum capability of electric vehiclesconnected to those dispensers. As an example, consider the total amountof power that can be supplied by the power modules 115A-L to be 375 kW,and each of the dispensers 150A-B may be rated to dispense 350 kW. Inorder to not exceed the power capacity of the power cabinet 110 (whichmay cause a circuit breaker to trip if exceeded), the sum of the powerdraw of the dispensers 150A-B should be less than or equal to the totalamount of power that can be supplied by the power modules 115A-L. Asanother example, if the EV 170A (capable of drawing 250 kW in thisexample) and the EV 170B (capable of drawing 150 kW in this example) aresimultaneously connected to the dispensers 150A-B, the electric vehiclescannot both receive their maximum capability as that would exceed thetotal amount of power that can be supplied by the power modules 115A-L.

The allocation of the power modules 115A-L between the dispensers 150A-Bcan be done differently in different embodiments. For example, theallocation may be done on a first-come first-served basis. As anotherexample, the allocation may be done on a round-robin basis. As anotherexample, the allocation may be done dynamically and be based on a set ofone or more factors.

FIG. 2 illustrates an example of allocating power modules according toan embodiment. In the example of FIG. 2, the EV 170A is capable ofdrawing 250 kW, the EV 170B is capable of drawing 150 kW, and the totalamount of power that can be supplied by the power modules 115A-L is 375kW (each capable of supplying 31.25 kW). The EV 170A arrives andconnects to the dispenser 150A at a time 1. At time 1, the EV 170B isnot connected to the dispenser 150B. Since at time 1 there are no powermodules allocated to either of the dispensers 150A-B and the amount ofpower that can be supplied by the power modules 115A-L is greater thanthe capability of the EV 170A, at a time 2, the group of power modules220 (the power modules 115A-H) are allocated to the dispenser 150A andare capable of supplying the maximum power capability of the EV 170A(250 kW). For instance, the power modules 115A-H are switchablyconnected to the power bus 140A.

In an embodiment, the dispenser 150A sends a request for power to thepower cabinet 110 (e.g., to the PCU 120) which in turn determines thateach of the power modules 115A-L are available and allocates each of thepower modules 115A-L to the dispenser 150A. The request may be sentafter the EV 170A is connected to the dispenser 150A and after thedesired amount of power is determined for the EV 170A. As anotherexample, the request may be sent prior to the EV 170A arriving to thedispenser 150A. For instance, if the EV 170A has a reservation at thedispenser 150A, the dispenser 150A may send the request for power to thepower cabinet 110 at a time prior to and proximate to the reservationtime. If the EV 170A does not show up for the reservation, the dispenser150A may release the allocated power modules. As another example,through use of telemetry such as the navigation of the EV 170A and/or anapp on a mobile device of an EV operator of the EV 170A, the dispenser150A may send the request for power to the power cabinet 110 at a timewhen the EV 170A is determined to be near the dispenser 150A.

Sometime later, at a time 3, the EV 170B arrives and is connected to thedispenser 150B. At time 3, the EV 170A is still connected to thedispenser 150A and the group of power modules 220 are switchablyconnected to the power bus 140A. Thus, at time 3, the power modules115A-H are not available to be allocated to the dispenser 150B. Sincethere is not enough remaining available power modules to allocate to thedispenser 150B to meet the maximum capability of the EV 170B, theremaining number of available power modules are allocated to thedispenser 150B. Thus, at a time 4, the group of power modules 225 (thepower modules 115I-L) are allocated to the dispenser 150B and arecapable of supplying 125 kW. For instance, the power modules 115I-L areswitchably connected to the power bus 140B.

If the EV 170A becomes disconnected from the dispenser 150A and/orfinishes charging, the group of power modules 220 may become available.For instance, the group of power modules 220 are switchably disconnectedfrom the power bus 140A. Since the EV 170B is capable of more power thanis currently allocated, some of the now available power modules may beallocated to the dispenser 150B. For instance, in this example, sincethe EV 170B is capable of drawing 150 kW and is currently allocated 4power modules each capable of supplying 31.25 kW (a total of 125 kW),another power module capable of supplying 31.25 kW (a total of 156.25kW) is allocated to the dispenser 150B so that the EV 170B can charge atits maximum capability.

In an embodiment, the allocation of the power modules 115A-L to thedispensers 150A-B is dynamic. For instance, FIG. 3 illustrates anexample of allocating power modules dynamically according to anembodiment. The example of FIG. 3 is an extension of the example of FIG.2. At time 5, the number of power modules allocated to the dispenser150A is reduced. For instance, the power module 115H, previouslyallocated to the dispenser 150A, is deallocated from the dispenser 150A(e.g., switchably disconnected from the power bus 140A). The remaininggroup of power modules 320 (the power modules 115A-G) remain allocatedto the dispenser 150A. Thus, the amount of power that is capable ofbeing drawn through the dispenser 150A has been reduced from 250 kW to218.75 kW. After deallocating the power module 115H from the dispenser150A, that power module is available to be allocated to a differentdispenser (e.g., the dispenser 150B). At time 6, the number of powermodules allocated to the dispenser 150B is increased. For instance, thepower module 115H is allocated to the dispenser 150B (e.g., switchablyconnected to the power bus 140B) and is part of the group of powermodules 325 allocated to the dispenser 150B (the power modules 115H-L).Thus, the amount of power that is capable of being drawn through thedispenser 150B has been increased from 125 kW to 156.25 kW.

The decision to dynamically allocate the power modules may be donedifferently in different embodiments. In an embodiment, the powermodules may be allocated across the different dispensers such that eachof the dispensers are allocated at least some power modules (assumingthat an EV is connected to the dispenser and is ready to accept energy),where the allocation may be on-demand (that is only if an electricvehicle is connected to that dispenser and requesting service). Thepower module allocation can be dynamically adjusted (either increased ordecreased) to a particular dispenser based on a set of one or morefactors. The set of factors may include one or more properties of activecharging sessions on the dispensers, one or more properties of thedispensers (e.g., the maximum rate of power that can be dispensed byeach dispenser, the current rate of power that is being dispensed byeach dispenser, the number of dispensers that are requesting to providecharging service, the number of electric vehicle(s) expected to arriveat the dispenser), and load condition information. The one or moreproperties of the active charging sessions may include one or more of:the duration that each electric vehicle connected to the dispensers hasbeen charging; the duration that each electric vehicle connected to thedispensers has been parked in proximity to the dispensers; the timeremaining on each charging session; the type of account associated witheach charging session; the amount of current drawn by each electricvehicle connected to the dispensers; the percentage of charge completeof each electric vehicle connected to the dispensers; the percentage ofcharge remaining of each electric vehicle connected to the dispensers;the battery temperature of each electric vehicle connected to thedispensers; the type of each electric vehicle connected to thedispensers; and a reservation status of each electric vehicle connectedto the dispensers.

The duration that the electric vehicles connected to the dispensers havebeen charging may be taken into consideration when determining how todynamically allocate power modules between those dispensers. Forinstance, a dispenser connected to an electric vehicle that has beencharging longer may be allocated less power modules than a dispenserconnected to an electric vehicle that has been charging relativelylesser.

The duration that the electric vehicles connected to the dispensers havebeen parked in proximity to the dispenser may be taken intoconsideration when determining how to dynamically allocate power modulesbetween those dispensers. For instance, a dispenser connected to anelectric vehicle that has been parked in proximity to the dispenserlonger may be allocated less power modules than a dispenser connected toan electric vehicle that has been parked in proximity to the dispenserfor a smaller amount of time.

The time remaining on the charging sessions may be taken intoconsideration when determining how to dynamically allocate power modulesbetween those dispensers. For instance, the allocation of power modulesmay prioritize charging sessions that are about to end.

The type of account associated with the charging sessions may be takeninto consideration when determining how to dynamically allocate powermodules between those dispensers. For example, a charging sessionassociated with an electric vehicle operator that is a member of aloyalty program of the host that owns or controls the dispensers may beprioritized over a charging session associated with an electric vehicleoperator that is not a member of the loyalty program. As anotherexample, a charging session associated with an electric vehicle operatorthat has paid a premium for charging service may be prioritized over acharging session associated with an electric vehicle operator that hasnot paid a premium for charging service.

The amount of current drawn by the electric vehicles connected to thedispensers may be taken into consideration when determining how todynamically allocate power modules between those dispensers. Forinstance, the allocation of power modules may prioritize a dispenserconnected to an electric vehicle that has drawn less current than adispenser connected to an electric vehicle that has drawn more current.

The percentage of charge complete of the electric vehicles connected tothe dispensers may be taken into consideration when determining how todynamically allocate power modules between those dispensers. Forinstance, the allocation of power modules may prioritize a dispenserconnected to an electric vehicle that has a lower percentage of chargecomplete over a dispenser connected to an electric vehicle that has ahigher percentage of charge complete.

The percentage of charge remaining of the electric vehicles connected tothe dispensers may be taken into consideration when determining how todynamically allocate power modules between those dispensers. Forinstance, the allocation of power modules may prioritize a dispenserconnected to an electric vehicle that has a higher percentage of chargeremaining over a dispenser connected to an electric vehicle that has alower percentage of charge remaining.

The battery temperature of the electric vehicles connected to thedispensers may be taken into consideration when determining how todynamically allocate power modules between those dispensers. Electricvehicles reduce their rate of charge when the battery temperaturereaches a certain amount. The allocation of power modules may prioritizea dispenser connected to an electric vehicle that has a lower batterytemperature over a dispenser connected to an electric vehicle that has ahigher battery temperature.

The type of the electric vehicles connected to the dispensers may betaken into consideration when determining how to dynamically allocatepower modules between those dispensers. For instance, the allocation ofpower modules may prioritize a dispenser connected to a battery onlyelectric vehicle (BEV) over a dispenser connected to a plug-in hybridelectric vehicle (PHEV).

The make and/or model of the electric vehicles connected to thedispensers may be taken into consideration when determining how todynamically allocate power modules between those dispensers. Forinstance, the allocation of power modules may prioritize a dispenserconnected to an electric vehicle of a certain make and/or model over adispenser connected to an electric vehicle of a different make and/ormodel.

A reservation status of the electric vehicles connected to thedispensers may be taken into consideration when determining how todynamically allocate power modules between those dispensers. Forinstance, an electric vehicle that has a valid reservation may beprioritized in the power module allocation over an electric vehicle thatdoes not have a valid reservation.

Load supply conditions may be taken into consideration when determininghow to dynamically allocate power modules. For instance, in periods ofhigh demand (sometimes referred to as a demand response event), amessage may be received that indicates that a reduction of power needsto be made. This may cause the total number of allocated power modulesto be decreased until the demand response ends.

The number of electric vehicle(s) expected to arrive at the dispenser(s)may be taken into consideration when determining how to dynamicallyallocate power modules between those dispensers. For example, if usehistory of the dispensers indicate that the dispensers are historicallybusy at a certain time (e.g., morning commute, afternoon commute), thepower modules may be allocated between those dispensers to supportmaximum use of the dispensers (e.g., the power modules may be allocatedequally between the dispensers). As another example, the predictedarrival of EVs (e.g., based on state of charge of the EV and vehiclenavigation information provided by an in-dash navigation unit and/or anapp of a mobile device of an EV operator) may be used to allocate thepower modules between those dispensers.

The allocation of power modules may be performed different in differentembodiments. In an embodiment, the allocation of power modules isperformed by the group of dispensers connected to the power cabinetthemselves. In another embodiment, the allocation of power modules isperformed by the power cabinet connected to the group of dispensers. Inanother embodiment, the allocation of power modules is performed by aserver that is connected with the power cabinet and/or group ofdispensers. In another embodiment, the allocation of power modules isperformed in cooperation with multiple entities (e.g., the dispensersand the network, the dispensers and the power cabinet). In any suchembodiment, the entity that determines the allocation of power moduleshas access to information that allows it to determine whether todynamically adjust the allocation of power modules. This information(e.g., duration that each electric vehicle connected to the dispensershas been charging; duration that each electric vehicle connected to thedispensers has been parked in proximity to the dispensers; the timeremaining on each charging session; the type of account associated witheach charging session; the amount of current drawn by each electricvehicle connected to the dispensers; the percentage of charge completeof each electric vehicle connected to the dispensers; the percentage ofcharge remaining of each electric vehicle connected to the dispensers;the battery temperature of each electric vehicle connected to thedispensers; the type of each electric vehicle connected to thedispensers; a reservation status of each electric vehicle connected tothe dispensers; the amount of power presently allocated to eachdispenser (or the number of power modules presently allocated to eachdispenser); the rate of power being dispensed by each dispenser; thenumber of electric vehicle(s) expected to arrive at the dispenser(s);and/or load condition information) may be stored and/or communicatedbetween the group of dispensers themselves, the power cabinet, and/orthe network.

In an embodiment where the group of dispensers determine how to allocatethe power modules of the power cabinet, upon a dispenser receiving arequest for charging service (e.g., an electric vehicle becomesconnected to the dispenser), the dispenser requests the status of thepower modules of the power cabinet. The dispenser may request the statusof each power module directly or through a request to the power cabinetwhich then queries the status of the power modules and returns thestatuses to the requesting dispenser. The status may also include anamount of time each power module has been operating. The dispenser usesthe status information of the power modules when determining how toallocate the power modules of the power cabinet.

FIG. 4 is a flow diagram that illustrates exemplary operations forallocating power modules according to an embodiment. The operations ofFIG. 4 will be described with respect to the exemplary embodiments ofthe other figures. However, it should be understood that the operationsof FIG. 4 can be performed by embodiments other than those discussedwith reference to the other figures, and the embodiments discussed withreference to these other figures can perform operations different thanthose discussed with reference to FIG. 4.

At operation 410, a dispenser receives a request to initiate chargingservice for an electric vehicle that is connected to the dispenser.Different electric vehicles may desire to draw different amount ofpowers. With respect to FIG. 2, for example, the EV 170A is capable ofdrawing 250 kW and the EV 170B is capable of drawing 150 kW. The requestto initiate charging service may indicate the desired amount of powerdraw. An electric vehicle operator may specify the desired amount ofpower draw. In an embodiment, the desired amount of power draw may bedetermined based on the model/make of the electric vehicle (which may bestored in association with an account of the electric vehicle operatorrequesting the charging service). In an embodiment, the electric vehicletransmits the requested power draw to the dispenser. Flow then moves tooperation 415.

At operation 415, the dispenser determines the amount of power that isavailable for charging service for the electric vehicle. For example,the dispenser 150A may send request the status of each power module115A-L of the power cabinet 110 directly or may send a request to thePCU 120 which then queries the status of the power modules 115A-L andreturns the statuses to the dispenser 150A, which indicates status ofthe power modules 115A-L. The status of each power module 115A-L mayinclude an amount of time each power module has been operating. Thestatus of each power module 115A-L may indicate the amount of power thatcan be supplied by that power module. In another embodiment, the powercabinet 110 periodically sends status information of the power modules115A-L to the dispensers 150A-B and/or to the network 180 (e.g., whenthe state of one of the power modules changes); which is used by thedispenser 150A to determine the amount of power that is available forcharging service. Next, flow moves to operation 420.

At operation 420, the dispenser determines whether the amount ofavailable power for charging the electric vehicle is enough to meet therequested or determined amount of power draw of the electric vehicle.For instance, the dispenser compares the amount of available power forcharging the electric vehicle with the requested or determined amount ofpower draw for the electric vehicle. If there is enough available powerfor charging the electric vehicle, then flow moves to operation 430. Ifthere is not enough available power for charging the electric vehicle,then flow moves to operation 425. For instance, in FIG. 2, there isenough power modules available to fully meet the power capability of theEV 170A when it is the only EV that is drawing power from the powermodules of the power cabinet 110; however there is not enough powermodules available to fully meet the power capability of the EV 170B ifthe EV 170A has been allocated power modules to fully meet its powercapability.

At operation 430, the dispenser selects the power modules to meet therequested or determined amount of power draw. In an embodiment, thedispenser only selects the power modules that have a status ofavailable. That is, the dispenser does not select from a power modulethat is currently allocated to another dispenser. From the availablepower modules, the dispenser may select those power module(s) that havethe relatively lowest operating time. The dispenser may transmit theidentification of the selected power modules to the other dispenser(s)connected to the power cabinet and/or to the network. Flow then moves tooperation 435. In another embodiment, instead of the dispenser selectingthe power modules, the dispenser requests a number of power modules andthe power cabinet selects the requested number of power modules andallocates them accordingly.

At operation 435, the dispenser requests allocation of the selectedpower modules. The requesting dispenser may send a command to each oneof the selected power modules directly (which may be relayed by the PCU120) that causes the selected power module to switchably connect to thepower bus that is connected to the dispenser. For instance, with respectto FIG. 1, the dispenser 150A may transmit a command to the selectedones of the power modules 115A-L (over the communication link 162) thatcauses those power modules to switchably connect to the power bus 140A.Flow then moves to operation 440 where charging service commences.

Flow moves from operation 440 to operation 460 where upon chargingservice ending, the dispenser requests deallocation of the allocatedpower modules. The charging service may end as a result of the chargingsession ending (e.g., the electric vehicle being disconnected from thedispenser). The requesting dispenser may send a command to each one ofthe allocated power modules directly (which may be relayed by the PCU120) that causes the allocated power module to switchably disconnectfrom the power bus that is connected to the dispenser. For instance,with respect to FIG. 1, the dispenser 150A may transmit a command to theallocated ones of the power modules 115A-L (over the communication link162) that causes those power modules to switchably disconnect from thepower bus 140A. As another example, the requesting dispenser may send acommand to the power cabinet that indicates that the dispenser hasfinished charging service and any allocated power module(s) may bedeallocated from the dispenser. In an embodiment, when a power module isdeallocated, it may be switchably disconnected from the power busimmediately. In another embodiment, when a power module is deallocated,it is not switchably disconnected from the power bus unless and until adetermination has been made to allocate that power module to anotherdispenser.

At operation 425, the dispenser determines whether there is any poweravailable for charging of the electric vehicle. If there is, then flowmoves to operation 445 where the dispenser requests allocation of theremaining power modules, in a similar way as described with respect tooperation 435. Flow then moves from operation 445 to operation 440. Ifthere is not any power available, then flow moves to operation 450 wherean alternative action is taken.

One alternative action is to wait until there is power available forcharging the EV. The dispenser may periodically request the status ofeach power module of the power cabinet to determine when there is poweravailable for charging the EV. Alternatively, the power cabinet and/orthe other dispenser(s) that have been allocated power module(s) mayperiodically send status information of the power modules to thedispenser and/or to the network that can be accessed or transmitted tothe dispenser.

Another alternative action is a dynamic allocation of the power moduleswhere one or more power modules are deallocated from a differentdispenser and allocated to the requesting dispenser. The dynamicallocation may be based on a set of one or more factors as previouslydescribed, and a set of predefined allocation rules. In an embodiment,the dynamic allocation of the power modules is performed by the group ofdispensers connected to the power cabinet themselves. In anotherembodiment, the dynamic allocation of power modules is performed by thepower cabinet connected to the group of dispensers. In anotherembodiment, the dynamic allocation of power modules is performed by aserver that is connected with the power cabinet and/or group ofdispensers. In another embodiment, the allocation of power modules isperformed in cooperation with multiple entities (e.g., the dispensersand the network, the dispensers and the power cabinet).

FIG. 5 is a flow diagram that illustrates exemplary operations fordynamic allocation of the power modules according to an embodiment. Theoperations of FIG. 5 will be described with respect to the exemplaryembodiments of the other figures. However, it should be understood thatthe operations of FIG. 5 can be performed by embodiments other thanthose discussed with reference to the other figures, and the embodimentsdiscussed with reference to these other figures can perform operationsdifferent than those discussed with reference to FIG. 5.

At operation 510, a determination has been made to dynamically allocatethe power modules between the dispensers connected to the power cabinet.The determination to dynamically allocate the power modules may be madeas a result of the sum of the requested power draw of the connecteddispensers exceeding the maximum amount supported by the power cabinet.In an embodiment, a dispenser that is allocated a power module isperiodically checked whether it is utilizing its allocated powermodule(s), and if it is not utilizing its allocated power module(s),those power module(s) are deallocated and allocated to a differentdispenser (if that dispenser has need for those power module(s)). Forinstance, an electric vehicle may ramp down its power usage as it isnearing charging completion, although it may still be connected to thedispenser. In such a situation, that EV may not need some or all of thepower modules that are currently allocated to the dispenser for the EV.In an embodiment, the EV may indicate to the dispenser the rate of powerthat it currently desires (e.g., the EV may send a current command tothe dispenser that can be used to determine how much power to supply tothe EV). In another embodiment, the rate of power that is beingdispensed through an EV is measured, and that measured amount iscompared against the allocated power amount to determine whether theallocated power module(s) are being utilized. The metrology componentmay be included within each dispenser, coupled with each dispenser,and/or included in the power cabinet.

Next, at operation 515, one or more of the dispensers connected to thepower cabinet that are currently allocated one or more power modules areselected to have one or more power modules be deallocated andreallocated to a different dispenser. Next, at operation 520, the numberof power module(s) currently allocated to the selected dispenser(s) tobe deallocated and reallocated to a different dispenser is determined.The decision to select a dispenser for power module deallocation, and/orthe selection of the number of power module(s) to be deallocated, maytake into consideration one or more factors, such as the duration thateach electric vehicle connected to the dispensers has been charging; theduration that each electric vehicle connected to the dispensers has beenparked in proximity to the dispensers; the time remaining on eachcharging session; the type of account associated with each chargingsession; the amount of current drawn by each electric vehicle connectedto the dispensers; the percentage of charge complete of each electricvehicle connected to the dispensers; the percentage of charge remainingof each electric vehicle connected to the dispensers; the batterytemperature of each electric vehicle connected to the dispensers; thetype of each electric vehicle connected to the dispensers; a reservationstatus of each electric vehicle connected to the dispensers; the amountof power presently allocated to each dispenser (or the number of powermodules presently allocated to each dispenser); the rate of power beingdispensed by each dispenser; the number of electric vehicle(s) expectedto arrive at the dispenser(s); and/or load condition information. Flowmoves from operation 520 to operation 525.

At operation 525, the selected number of power module(s) fordeallocation are deallocated from dispenser(s) in which it is currentlyconnected, and reallocated to another dispenser. For example, withreference to FIG. 3, the power module 115H that was previously allocatedto the dispenser 150A is deallocated (e.g., switchably disconnected fromthe power bus 140A) and allocated to the dispenser 150B (e.g.,switchably connected to the power bus 140B). To deallocate a powermodule from a dispenser, a message may be sent from the dispenser tothat power module directly (which may be relayed by the PCU of the powercabinet) that instructs the power module to switchably disconnect fromthe power bus. That dispenser may also instruct the power module to beallocated to a different dispenser. Alternatively, the dispenser that isdeallocating the power module may send a message to the dispenser thatwill be allocated that power module that indicates that the power modulehas been instructed to be disconnected. The dispenser that will beallocated that power module may then send a message to the power modulethat causes the power module to be switchably connected to the power busconnecting the dispenser with the power cabinet.

In an embodiment, a dispenser sends a request for power to the powercabinet which in turn allocates the available power modules to thedispenser, regardless of whether the amount of allocated power exceedsthe requested or supported amount of power. If the dispenser isallocated an excess amount of power, the dispenser releases the excesspower module(s) so that they can be allocated to a different dispenser.

FIG. 6 is a flow diagram that illustrates exemplary operations forallocating power modules according to an embodiment. The operations ofFIG. 6 will be described with respect to the exemplary embodiments ofthe other figures. However, it should be understood that the operationsof FIG. 6 can be performed by embodiments other than those discussedwith reference to the other figures, and the embodiments discussed withreference to these other figures can perform operations different thanthose discussed with reference to FIG. 6.

At operation 610, a dispenser sends a request for power to the powercabinet. The request may be sent in reaction to an electric vehiclebeing connected to the dispenser. Alternatively, the request may be sentproactively such as based upon a reservation time of the dispensernearing (within a predetermined time of the reservation time) or throughdetermining a likelihood that an electric vehicle will be arriving atthe dispenser (e.g., through history of use or through use of navigationand state of charge of the EV). The power cabinet receives the requestand will allocate any available power modules to the requestingdispenser.

Next, at operation 615, the dispenser receives a message from the powercabinet that indicates an allocation of one or more power modules fromthe power cabinet. The message may include information about theallocated power modules (e.g., an identifier of each power module thathas been allocated to the dispenser, an amount of time each allocatedpower module has been operating, and/or the amount of power that can bedispensed by each allocated power module).

The number of power modules and corresponding power may exceed therequested/determined or supported amount of power draw from the electricvehicle connected to the dispenser or expected to be connected to thedispenser. At operation 620, the dispenser determines whether the numberof allocated power modules exceed the requested or determined amount ofpower draw for the electric vehicle. For instance, the dispensercompares the amount of allocated power with the requested or determinedamount of power draw for the electric vehicle. For instance, withrespect to FIG. 2, if the dispenser 150A is initially allocated all ofthe power modules 115A-L and each is capable of supplying 31.25 kW (atotal of 375 kW), the total amount of power (375 kW) exceeds the amountof power that is capable of being drawn by the EV 170A (250 kW). If theamount of allocated power modules exceed the requested or determinedamount of power draw for the EV, then flow moves to operation 630. Ifthe amount of allocated power modules does not exceed the requested ordetermined amount of power draw for the EV, then flow moves to operation640.

At operation 630, the dispenser selects one or more power modules torelease such that the total amount of power does not exceed therequested or determined amount of power draw for the EV. For instance,with respect to FIG. 2, if the power modules 115A-L are all allocated tothe dispenser 150A, the dispenser 150A may select four of those modules(a total of 125 kW) to release so that they can be allocated to thedispenser 150B. In an embodiment, the dispenser selects the powermodules to release that have the most amount of operating hours. Flowthen moves to operation 635 where the dispenser requests deallocation ofthe selected power modules. The requesting dispenser may send a commandto each one of the allocated power modules directly (which may berelayed by the PCU 120) that causes the allocated power module toswitchably disconnect from the power bus that is connected to thedispenser. As another example, the requesting dispenser may send amessage to the power cabinet that indicates that it has released theselected power modules (the message may indicate an identifier of eachof the selected power modules). In an embodiment, when a power module isdeallocated, it may be switchably disconnected from the power busimmediately. In another embodiment, when a power module is deallocated,it is not switchably disconnected from the power bus unless and until adetermination has been made to allocate that power module to anotherdispenser. Flow then moves to operation 640, where charging servicecommences. In an embodiment, commencing of the charging service ofoperation 640 may be prior to the operation 630. Flow moves fromoperation 640 to operation 650.

At operation 650, upon charging service ending, the dispenser requestsdeallocation of the allocated power modules. The charging service mayend as a result of the charging session ending (e.g., the electricvehicle being disconnected from the dispenser). The requesting dispensermay send a command to each one of the allocated power modules directly(which may be relayed by the PCU 120) that causes the allocated powermodule to switchably disconnect from the power bus that is connected tothe dispenser. For instance, with respect to FIG. 1, the dispenser 150Amay transmit a command to the allocated ones of the power modules 115A-L(over the communication link 162) that causes those power modules toswitchably disconnect from the power bus 140A. As another example, therequesting dispenser may send a command to the power cabinet thatindicates that the dispenser has finished charging service and anyallocated power module(s) may be deallocated from the dispenser. In anembodiment, when a power module is deallocated, it may be switchablydisconnected from the power bus immediately. In another embodiment, whena power module is deallocated, it is not switchably disconnected fromthe power bus unless and until a determination has been made to allocatethat power module to another dispenser.

At any time after the charging service has commenced or after the powermodules have been allocated, a dynamic reallocation of power modules maybe performed, such as described with respect to FIG. 5.

Selecting Power Module(s) for Allocation

As previously described herein, the number of power module(s) that areallocated to dispenser(s) may be determined dynamically. In anembodiment, the particular power module(s) that will be selected forallocation is dynamically determined. For instance, the selection ofpower module(s) for allocation may be performed according to a loadbalancing algorithm such that the usage amongst the power modules isroughly equal. This helps preventing a power module from wearing outfaster than others due to overuse. In an embodiment, upon determiningthat a power module is to be allocated to a dispenser, the operatinghours of the available power modules is determined and the power modulewith the lowest amount of operating hours is selected for allocation.

Deallocating a Power Module

Reference has been made herein to deallocating a power module. In anembodiment, deallocating a power module includes disconnecting the powermodule from the power bus in which it is currently connected. Forinstance, the PCU 120 may cause the power module to be switchablydisconnected from the power bus in which it is currently disconnected. Adeallocated power module is then available to be allocated. In anotherembodiment, deallocating a power module does not include disconnectingthe power module from the power bus in which it is currently connectedunless and until a determination has been made to allocate that powermodule to another dispenser.

Split Panel

Although FIGS. 1-3 illustrate the power modules of the power cabinetbeing able to be allocated to a single set of dispensers; in otherembodiments a first group of the power modules of the power cabinet maybe able to be allocated to a first set of dispensers and a second groupof the power modules of the power cabinet may be able to be allocated toa second set of dispensers. For instance, FIG. 7 illustrates anembodiment where the power cabinet 110 is split into multiple powermodule groups 710 and 720 where the members of the power module group710 (the power modules 115A-F) can be dynamically allocated to a firstset of dispensers 150A-B via the output 152A-B and the members of thegroup 720 (the power modules 115G-L) can be dynamically allocated to asecond set of dispensers 150C-D via the output 152C-D.

Dispenser

FIG. 8 illustrates an exemplary dispenser according to an embodiment.The dispensers 150A-D may take the form of the dispenser 800. Thedispenser 800 includes the operating system 810 that is coupled with theembedded microcontroller 815. The operating system 810 manages certainhardware and software for the dispenser 800 such as the WAN module 850to manage a wide area network (WAN) connection for the dispenser 800,the LCD module 855 to manage a display of the dispenser 800, and theRFID module 860 that manages an RFID transceiver of the dispenser 800.The embedded microcontroller 815 executes the isolation detect module865, the contactor control module 870, the metrology module 875, theJ1772 communications module 880, the CHAdeMO communications module 885,and the cooling control module 890. Of course, it should be understoodthat the dispenser may include more, less, or different communicationmodules for communicating with different vehicle types.

The isolation detect module 865 manages the isolation sensor 825 todetect whether the circuits are isolated. For instance, with respect toa DC output, rail isolation is the resistance between each DC rail andground including any measuring device, and total isolation is theparallel combination of both rail isolation values. The dispenser 800will terminate a charge when the isolation of either rail to ground isunder a certain amount. The contactor control module 870 manages thecontactor 830 including causing the contactor 830 to open and close asappropriate. The V/I sense component 820 senses the current and voltageand provides the sensed data to the embedded microcontroller 815.

The metrology module 875 manages the metrology component 840 that meterselectrical usage (e.g., drawn by the electric vehicle). The J1772communications module 880 handles communications between the dispenser800 and an electric car according to the J1772 standard. The CHAdeMOcommunications module 885 handles communications between the dispenser800 and an electric car according to the CHAdeMO standard.

The cooling control module 890 manages the cooling of the dispenser 800including managing the cable cooling component 835. The cable coolingcomponent 835 may control a liquid cable cooling system, and may monitorand control the flow rate, pressure, inlet, outlet temperature, cabletemperature, and/or connector temperature of the charging cable.

The techniques shown in the figures can be implemented using code anddata stored and executed on one or more electronic devices (e.g., adispenser, a power cabinet, a server). Such electronic devices store andcommunicate (internally and/or with other electronic devices over anetwork) code and data using machine-readable media, such asnon-transitory machine-readable storage media (e.g., magnetic disks;optical disks; random access memory; read only memory; flash memorydevices; phase-change memory) and transitory machine-readablecommunication media (e.g., electrical, optical, acoustical or other formof propagated signals—such as carrier waves, infrared signals, digitalsignals). In addition, such electronic devices typically include a setof one or more processors coupled to one or more other components, suchas one or more storage devices (non-transitory machine-readable storagemedia), user input/output devices (e.g., a keyboard, a touchscreen,and/or a display), and network connections. The coupling of the set ofprocessors and other components is typically through one or more bussesand bridges (also termed as bus controllers). Thus, the storage deviceof a given electronic device typically stores code and/or data forexecution on the set of one or more processors of that electronicdevice. Of course, one or more parts of an embodiment of the inventionmay be implemented using different combinations of software, firmware,and/or hardware.

While the flow diagrams in the figures show a particular order ofoperations performed by certain embodiments of the invention, it shouldbe understood that such order is exemplary (e.g., alternativeembodiments may perform the operations in a different order, combinecertain operations, overlap certain operations, etc.).

References in the specification to “one embodiment,” “an embodiment,”“an example embodiment,” etc., indicate that the embodiment describedmay include a particular feature, structure, or characteristic, butevery embodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed.

Bracketed text and blocks with dashed borders (e.g., large dashes, smalldashes, dot-dash, and dots) may be used herein to illustrate optionaloperations that add additional features to embodiments of the invention.However, such notation should not be taken to mean that these are theonly options or optional operations, and/or that blocks with solidborders are not optional in certain embodiments of the invention.

The term “coupled,” along with its derivatives, may be used in thisdescription. “Coupled” is used to indicate that two or more elements,which may or may not be in direct physical or electrical contact witheach other, co-operate or interact with each other.

While the invention has been described in terms of several embodiments,those skilled in the art will recognize that the invention is notlimited to the embodiments described, can be practiced with modificationand alteration within the spirit and scope of the appended claims. Thedescription is thus to be regarded as illustrative instead of limiting.

What is claimed is:
 1. An apparatus, comprising: a housing; a pluralityof power modules included within the housing, wherein each of the powermodules is capable of supplying an amount of power to a dispenser; afirst power bus that is coupled to a first dispenser and switchablyconnected to the plurality of power modules; a second power bus that iscoupled to a second dispenser and switchably connected to the pluralityof power modules; and a control unit that is coupled to the plurality ofpower modules, the first dispenser, and the second dispenser, andwherein the control unit is configured to: cause the plurality of powermodules to switchably connect and disconnect from the first power busand the second power bus to dynamically allocate the plurality of powermodules between the first dispenser and the second dispenser.
 2. Theapparatus of claim 1, wherein the dynamic allocation of the plurality ofpower modules between the first dispenser and the second dispenser isbased on a set of one or more factors including one or more propertiesof active charging sessions on the first dispenser and the seconddispenser.
 3. The apparatus of claim 2, wherein the one or moreproperties of the active charging sessions include for each chargingsession, one or more of: a duration that each electric vehicle connectedto the first dispenser and the second dispenser has been charging, aduration that each electric vehicle connected to the first dispenser andthe second dispenser has been parked in proximity to the first dispenserand the second dispenser, a time remaining on each charging session, atype of account associated with each charging session, an amount ofcurrent drawn by each electric vehicle connected to the first dispenserand the second dispenser, a percentage of charge complete of eachelectric vehicle connected to the first dispenser and the seconddispenser, a percentage of charge remaining of each electric vehicleconnected to the first dispenser and the second dispenser, a batterytemperature of each electric vehicle connected to the first dispenserand the second dispenser, a type of each electric vehicle connected tothe first dispenser and the second dispenser, and a reservation statusof each electric vehicle connected to the first dispenser and the seconddispenser.
 4. The apparatus of claim 2, wherein the set of one or morefactors further includes one or more of: a maximum rate of power thatcan be dispensed by each of the first dispenser and the seconddispenser, and load supply condition.
 5. The apparatus of claim 1,wherein the control unit is further configured to transmit, to the firstdispenser and the second dispenser, status of the plurality of powermodules.
 6. The apparatus of claim 5, wherein the status of theplurality of power modules specifies an amount of operating time of eachof the plurality of power modules.
 7. A dispenser to charge electricvehicles, comprising: a processor; a non-transitory machine-readablestorage medium that stores instructions that, when executed by theprocessor, cause the processor to perform the following: request powerfrom a power cabinet that includes a plurality of power modules forcharging an electric vehicle, wherein the dispenser is one of aplurality of dispensers that are supplied power by the power cabinet,wherein each power module can be allocated to a single one of thedispensers at a time, and wherein the power cabinet includes a pluralityof power modules that together support less than a complete utilizationof the plurality of dispensers, receive a message that indicates anallocation of one or more of the power modules, and in response to adetermination that an amount of allocated power modules exceeds anamount of power requested or determined for charging the electricvehicle, send a message to the power cabinet to release the amount ofallocated power modules so that they are available to be allocated toanother one of the plurality of dispensers.
 8. The dispenser of claim 7,wherein the non-transitory machine-readable storage medium furtherstores instructions that, when executed by the processor, cause theprocessor to perform the following: in response to a determination todynamically allocate the plurality of power modules between theplurality of dispensers, participate in a dynamic allocation of theplurality of power modules to the plurality of dispensers wherein atleast one of the plurality of power modules that is presently allocatedto the dispenser is deallocated and reallocated to another one of theplurality of dispensers.
 9. The dispenser of claim 8, wherein thedynamic allocation of the plurality of power modules between theplurality of dispensers is based on a set of one or more factorsincluding one or more properties of active charging sessions on theplurality of dispensers.
 10. The dispenser of claim 9, wherein the oneor more properties of the active charging sessions include for eachcharging session, one or more of: a duration that each electric vehicleconnected to the plurality of dispensers has been charging, a durationthat each electric vehicle connected to the plurality of dispensers hasbeen parked in proximity to the plurality of dispensers, a timeremaining on each charging session, a type of account associated witheach charging session, an amount of current drawn by each electricvehicle connected to the plurality of dispensers, a percentage of chargecomplete of each electric vehicle connected to the plurality ofdispensers, a percentage of charge remaining of each electric vehicleconnected to the plurality of dispensers, a battery temperature of eachelectric vehicle connected to the plurality of dispensers, a type ofeach electric vehicle connected to the plurality of dispensers, and areservation status of each electric vehicle connected to the pluralityof dispensers.
 11. The dispenser of claim 9, wherein the set of one ormore factors further includes one or more of: a maximum rate of powerthat can be dispensed by each of the plurality of dispensers, and loadsupply condition.
 12. The dispenser of claim 7, wherein the dispenser isto select the amount of allocated power modules to release based onoperating time of each of the plurality of power modules.
 13. A method,comprising: requesting power from a power cabinet that includes aplurality of power modules for charging an electric vehicle, wherein thedispenser is one of a plurality of dispensers that are supplied power bythe power cabinet, wherein each power module can be allocated to asingle one of the dispensers at a time, and wherein the power cabinetincludes a plurality of power modules that together support less than acomplete utilization of the plurality of dispensers, receiving a messagethat indicates an allocation of one or more of the power modules, andresponsive to determining that an amount of allocated power modulesexceeds an amount of power requested or determined for charging theelectric vehicle, sending a message to the power cabinet to release theamount of allocated power modules so that they are available to beallocated to another one of the plurality of dispensers.
 14. The methodof claim 13, further comprising, responsive to determining todynamically allocate the plurality of power modules between theplurality of dispensers, participating in a dynamic allocation of theplurality of power modules to the plurality of dispensers wherein atleast one of the plurality of power modules that is presently allocatedto the dispenser is deallocated and reallocated to another one of theplurality of dispensers.
 15. The method of claim 14, wherein the dynamicallocation of the plurality of power modules between the plurality ofdispensers is based on a set of one or more factors including one ormore properties of active charging sessions on the plurality ofdispensers.
 16. The method of claim 15, wherein the one or moreproperties of the active charging sessions include for each chargingsession, one or more of: a duration that each electric vehicle connectedto the plurality of dispensers has been charging, a duration that eachelectric vehicle connected to the plurality of dispensers has beenparked in proximity to the plurality of dispensers, a time remaining oneach charging session, a type of account associated with each chargingsession, an amount of current drawn by each electric vehicle connectedto the plurality of dispensers, a percentage of charge complete of eachelectric vehicle connected to the plurality of dispensers, a percentageof charge remaining of each electric vehicle connected to the pluralityof dispensers, a battery temperature of each electric vehicle connectedto the plurality of dispensers, a type of each electric vehicleconnected to the plurality of dispensers, and a reservation status ofeach electric vehicle connected to the plurality of dispensers.
 17. Themethod of claim 15, wherein the set of one or more factors furtherincludes one or more of: a maximum rate of power that can be dispensedby each of the plurality of dispensers, and load supply condition. 18.The method of claim 13, wherein the dispenser is to select the amount ofallocated power modules to release based on operating time of each ofthe plurality of power modules.